Update SetVector to rely on the underlying set's insert to return a pair<iterator, bool>

This is to be consistent with StringSet and ultimately with the standard
library's associative container insert function.

This lead to updating SmallSet::insert to return pair<iterator, bool>,
and then to update SmallPtrSet::insert to return pair<iterator, bool>,
and then to update all the existing users of those functions...

llvm-svn: 222334
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
index 8f8627a..8f582f1 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -2760,7 +2760,7 @@
   SmallSet<BasicBlock*, 32> Done;
   for (unsigned i = 0, e = I.getNumSuccessors(); i != e; ++i) {
     BasicBlock *BB = I.getSuccessor(i);
-    bool Inserted = Done.insert(BB);
+    bool Inserted = Done.insert(BB).second;
     if (!Inserted)
         continue;
 
@@ -7697,7 +7697,8 @@
 
     // If this terminator has multiple identical successors (common for
     // switches), only handle each succ once.
-    if (!SuccsHandled.insert(SuccMBB)) continue;
+    if (!SuccsHandled.insert(SuccMBB).second)
+      continue;
 
     MachineBasicBlock::iterator MBBI = SuccMBB->begin();